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