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