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