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