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