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