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