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