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