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)(11,19)(12,24,28,17)(13,30)(14,31)(15,18)(16,22)(20,38,25,36)(21,33)(23,37)(26,29,35,27)(32,39,34,40)(1,3)(2,5)(4,7)(6,8)(9,11,14,22,15,23,30,33)(10,16,13,19,18,21,31,37)(12,25,27,40,28,20,29,39)(17,34,26,38,24,32,35,36)(3,7)(5,8)(9,12)(10,17)(11,20)(13,26)(14,27)(15,28)(16,32)(18,24)(19,36)(21,34)(22,39)(23,25)(29,30)(31,35)(33,40)(37,38) involution — undirected(9,13,14,10,15,31,30,18)(11,21,22,19,23,16,33,37)(12,26,27,17,28,35,29,24)(20,34,39,36,25,32,40,38)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.