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