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