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