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