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