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