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