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