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