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