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