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