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)(11,15)(12,16)(13,14)(17,20)(18,22)(19,21)(23,24)(25,26,30,33)(27,31,29,35)(28,36,39,40)(32,37,38,34)(3,7)(5,8)(10,14)(15,20)(16,21)(22,24)(25,27,30,29)(26,31,33,35)(28,37,39,34)(32,36,38,40)(1,3)(2,5)(4,7)(6,8)(9,11)(10,15)(12,18)(13,17)(14,20)(16,22)(19,23)(21,24)(25,28,30,39)(26,32,33,38)(27,34,29,37)(31,40,35,36)(2,6)(3,7)(11,17)(15,20)(18,23)(22,24)(25,26)(27,35)(28,38)(29,31)(30,33)(32,39)(34,40)(36,37) involution — undirected(9,12,13,19)(10,16,14,21)(11,18,17,23)(15,22,20,24)(25,27,30,29)(26,31,33,35)(28,34,39,37)(32,40,38,36)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.