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