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