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