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