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