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