One vertex per element, one color per generator, with an edge from x to x·s.
(9,10)(11,17)(12,20)(13,15)(14,19)(16,22)(18,23)(21,24)(25,26)(27,28)(29,37)(30,32)(31,39)(33,35)(34,40)(36,38) involution — undirected(1,2,5,6)(3,4,7,8)(9,11,13,19)(10,14,15,17)(12,21,22,18)(16,24,20,23)(25,27,30,35)(26,28,32,33)(29,38,39,34)(31,40,37,36)(2,6)(3,7)(10,15)(14,17)(16,20)(23,24)(25,26,30,32)(27,33,35,28)(29,31,39,37)(34,40,38,36)(2,6)(3,7)(9,11)(10,14)(12,18)(13,19)(15,17)(16,23)(20,24)(21,22)(25,28)(26,27)(29,36)(30,33)(31,34)(32,35)(37,38)(39,40) involution — undirected(1,3)(2,4)(5,7)(6,8)(9,10)(11,14)(12,16)(13,15)(17,19)(18,23)(20,22)(21,24)(25,26)(27,28)(29,31)(30,32)(33,35)(34,36)(37,39)(38,40) involution — undirected(1,4)(2,3)(5,8)(6,7)(9,12,13,22)(10,16,15,20)(11,18,19,21)(14,23,17,24)(25,29)(26,31)(27,34)(28,36)(30,39)(32,37)(33,40)(35,38)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.