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