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