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