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