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