One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,6)(4,7)(5,8)(9,10,14,15)(11,13,17,21)(12,16,19,22)(18,20,23,24)(25,26,30,32)(27,28,34,36)(29,31,39,38)(33,35,37,40)(1,3)(2,4)(5,7)(6,8)(12,19)(16,22)(18,23)(20,24)(25,27)(26,28)(29,37)(30,34)(31,40)(32,36)(33,39)(35,38) involution — undirected(10,15)(11,17)(16,22)(18,23)(25,28,30,36)(26,27,32,34)(29,35,39,40)(31,33,38,37)(9,11)(10,13)(12,18)(14,17)(15,21)(16,20)(19,23)(22,24)(25,28)(26,27)(29,35)(30,36)(31,33)(32,34)(37,38)(39,40) involution — undirected(1,3)(2,6)(4,8)(5,7)(9,12)(10,16)(11,18)(13,20)(14,19)(15,22)(17,23)(21,24)(25,29)(26,31)(27,33)(28,35)(30,39)(32,38)(34,37)(36,40) involution — undirected(1,4,5,6)(2,7,8,3)(9,13)(10,11)(12,20)(14,21)(15,17)(16,18)(19,24)(22,23)(25,26)(27,28)(29,38)(30,32)(31,39)(33,40)(34,36)(35,37)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.