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