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