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