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