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