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)(28,33)(29,39)(30,32)(31,34)(36,37)(38,40)(3,7)(5,8)(9,10)(11,15)(12,16)(13,17)(14,19)(18,24)(20,23)(21,22)(25,27,31,30)(26,32,34,35)(28,36,39,38)(29,37,33,40)(1,2)(3,5)(4,6)(7,8)(9,11)(10,14)(12,18)(13,19)(15,17)(16,23)(20,22)(21,24)(25,28,31,39)(26,33,34,29)(27,36,30,38)(32,40,35,37)(9,11)(10,15)(12,20)(13,19)(14,17)(16,23)(18,22)(21,24)(25,29)(26,28)(27,37)(30,40)(31,33)(32,36)(34,39)(35,38) involution — undirected(1,3)(2,5)(4,7)(6,8)(9,10)(11,14)(12,21)(13,17)(15,19)(16,22)(18,24)(20,23)(25,26)(27,32)(28,33)(29,39)(30,35)(31,34)(36,40)(37,38) involution — undirected(1,2)(3,5)(4,6)(7,8)(9,12)(10,16)(11,18)(13,22)(14,23)(15,24)(17,21)(19,20)(25,30,31,27)(26,32,34,35)(28,38,39,36)(29,37,33,40)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.