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