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