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